Troubleshooting BGP neighbor between idle and Establish oscillation

Publication Date:  2013-12-10 Views:  967 Downloads:  0
Issue Description
AntiDDoS1550 and router BGP neighbor state, unable to establish stable neighbor state, the ‘display bgp peer’ found that neighbor state continuously from the idle->Establish->idle->Establish cycle oscillation.
Alarm Information
NA
Handling Process
Debug bgp found that the neighbor state oscillation between idle and establish.
%2013-09-11 18:38:21 Clean%%01BGP/3/STATE_CHG_UPDOWN (L): Peer 27.113.130.1 state was changed from OPENCONFIRM to ESTABLISHED. (BGP address family=public)
%2013-09-11 18:37:49 Clean%%01BGP/3/STATE_CHG_UPDOWN (L): Peer 27.113.130.1 state was changed from ESTABLISHED to IDLE. (BGP address family=public)
Debug information indicated that routes max number limit is reached, the AntiDDoS1550 disconnected the bgp peer.
%2013-09-11 18:37:49 Clean%%01BGP/3/ROUTEADD_REACHLMT (L): Route updating failed in public instance. Max route limit reached.
%2013-09-11 18:37:49 Clean%%01RM/3/SYS_RCH_MAX_RT_LMT (L): Number of routes reached maximum route limit 100000 of whole system when checking the route limit in routing table.
Because the AntiDDoS1550 can only accept 100000 routes, when the routes number exceeds the design specifications will disconnect from the BGP neighbor.
Because the cleaning equipment just to inform the diversion route to neighbor, doesn't need to learn all routes from the neighbor equipment, therefore prohibited to import any route information from the core router, or the core router equipment prohibits to redistribute the route information to the cleaning equipment.
In the case, the customer configured the route policy filter the route in the core router solved the problem.

Root Cause
Possible reasons: the connection timeout and configuration error, etc.
Suggestions
If the core router has running BGP already, it is need to pay attention to the route policy in the core router or cleaning equipment, normally, the Cleaning device itself does not need the all network routes.

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